Recently various kinds of digital audio disks have been sold, and the utilization thereof has been remarkably expanding. Various kinds of multi-disk players by which six to ten disks can be consecutively played have been developed. Many of these multi-disk players are of such a type that consecutive playing can be made available by vertically shifting the whole light pick-up block which can read signals by using laser light. Since a heavy light pick up block is vertically driven, a mechanism to drive the light pick up block is complicated in structure and expensive.
The conventional multi-disk player mentioned above is explained below:
FIG. 8 shows a conventional type of multi-disk player. In FIG. 8, a disk 102 placed on a disk holder 101a of a tray 101 is arranged and stored by turns in the six-storied shelves 103a which are formed in a magazine 103, and the disk 102 can be freely drawn out from and stored in these shelves.
The reference numeral 104 is the mechanism body of the multi-disk player, and the above magazine 103 is always housed at a fixed position in a box-like magazine base 105 to house the magazine.
The reference numeral 106 is a magazine push-out lever which is pushed in the direction of A by insertion of the magazine 103 at all times, and the magazine push-out lever is so composed that it can be pushed out in the direction of B by means of a spring 107.
The reference numeral 108 is a magazine lock lever to lock the magazine, and the magazine lock lever is so composed that it can be engaged by means of a drawing spring 109 with a dent 103b formed at a side wall of the magazine 103 and the magazine 103 can be prevented from being pushed out in the direction of B thereof.
The reference numeral 110 is a plunger which is so composed that the plunger 110 can disengage the magazine lock lever 108 from the dent 103b formed at a side wall of the magazine 103 by electric current flown to the plunger when taking out the magazine 103 and that the magazine 103 can be pushed out by the magazine push-out lever 106.
The reference numeral 111 is a speed control device to control the push-out speed of the magazine, which is so composed that it is pressure-fitted to the magazine push-out lever 106 and can control the push-out speed of the magazine 103.
The reference numeral 112 is a tray hook which is so composed that it can slide in either direction of A or B, being guided by a guide shaft 114 provided at a loading base 113 for feeding the tray 101 to the playing start position. The reference numeral 115 is a tray hook drive motor installed on the loading base, which can drive the tray hook 112 in either direction A and B by means of a pulley 116 and a belt 117, thereby causing the dent 101b of the tray 101 to be engaged with the above tray hook 112 and the tray 101 to be drawn out from the magazine 103 and to be housed in the same.
The reference numeral 118 is a tray guide which is located on the loading base 113 and is provided to start playing the disk 102 after the tray 101 is guided onto a turntable 120 of the light pick-up block 119.
The reference numeral 121 are threaded screws which are so composed that they can be fitted to female-threaded portions 122 installed at three points at the periphery of the loading base 113 to vertically elevate and lower the loading base 113 and that the loading base 113 can be vertically elevated and lowered.
The reference numeral 123 is a timing belt which drives the three threaded screws in engagement of small gears 124 provided at the lower part of each of the three threaded screws 121 and which can be driven by an elevating and lowering drive motor 125.
The operation of a multi-disk player so composed as mentioned above is explained below:
As the magazine 103 in which six disks 102 and the tray 101 are housed is inserted in the magazine base 105, the magazine 103 is locked at a fixed position by means of a push-back force of the magazine push-out lever 106 and the magazine lock lever 108. Next, the loading base 113 is elevated and lowered to revolution of the drive motor 125 and stops at a height where the tray hook 112 can be engaged with the dent 101b of the tray 101.
Subsequently, as the tray hook drive motor 115 rotates clockwise, the tray hook 112 draws out the tray 101 in the direction of A. Then, the motor 115 stops when the center of the disk 102 comes onto the center of the turntable 120, and the disk is started for playing.
The tray hook drive motor 115 rotates counterclockwise as the playing ends, the tray hook 112 pushes back the tray 101 in the direction of B and the tray 101 is housed in the magazine 103.
As current is supplied to the plunger 110, the magazine lock lever 108 is disengaged from the dent 103b of the magazine 103, thereby causing the magazine 103 to be pushed out in the direction of B by means of the magazine push-out lever 106 and causing the magazine to be taken out from the multi-disk player 104.
However, in the construction mentioned above, since the loading base 113 having a heavy light pick-up block 119, the tray hook drive motor, etc. are elevated and lowered by three threaded screws 121, a heavy-duty elevating and lowering structure is required. In addition, the whole structure becomes complicated and the production cost thereof becomes expensive.
Moreover, there is still another problem that since the weight of the whole loading base 113 is heavy it is impossible to quicken the elevating and lowering speed.